import React, { Component } from 'react';
import Board from './Board';

class Game extends Component {

    constructor(props){
        super(props);
        this.state = {
            history:[{
                squares:Array(9).fill(null),
            }],
            stepNumber:0,
            xIsNext:true,
        }
    }

    handleClick(i) {
        const history = this.state.history.slice(0, this.state.stepNumber + 1);
        const current = history[history.length - 1];
        const squares = current.squares.slice();
        if (calculateWinner(squares) || squares[i]) {
        return;
        }
        squares[i] = this.state.xIsNext ? 'X' : 'O';
        this.setState({
        history: history.concat([{
            squares: squares
        }]),
        stepNumber: history.length,
        xIsNext: !this.state.xIsNext,
        });
    }

    jumpTo(step) {
        this.setState({
            stepNumber: step,
            xIsNext: (step % 2) === 0,
        });
    }

    render() {
        const history = this.state.history;
        const current = history[this.state.stepNumber];
        const winner = calculateWinner(current.squares);

        const moves = history.map((step, move) => {
        const desc = move ?
            'Go to move #' + move :
            'Go to game start';
        return (
            <li key={move}>
            <button onClick={() => this.jumpTo(move)}>{desc}</button>
            </li>
        );
        });

        let status;
        if (winner) {
            status = 'Winner: ' + winner;
        } else {
            status = 'Next player: ' + (this.state.xIsNext ? 'X' : 'O');
        }
        return (
            <div className="game">
                <div className="game-board">
                <Board squares={current.squares} onClick={(i) => this.handleClick(i)} />
                </div>
                <div className="game-info">
                <div>{status}</div>
                <ol>{moves}</ol>
                </div>
            </div>
        );
    }
}


function calculateWinner(squares) {
  const lines = [
    [0, 1, 2],
    [3, 4, 5],
    [6, 7, 8],
    [0, 3, 6],
    [1, 4, 7],
    [2, 5, 8],
    [0, 4, 8],
    [2, 4, 6],
  ];
  for (let i = 0; i < lines.length; i++) {
    const [a, b, c] = lines[i];
    if (squares[a] && squares[a] === squares[b] && squares[a] === squares[c]) {
      return squares[a];
    }
  }
  return null;
}

export default Game;